As I live in Salt Lake City, too. What I would suggest is a long sleved white shirt, possibly with French Cuffs, Silver cuff links. I would pick a tie that matched one of the colors from the kilt, had white in it, and another complementary color. I would also recommend choosing to go with either brown, or black leathers, but not both. I would choose hose which is a cream color, or which matches the kilt. If you go to DI you can find a nice tweed sport jacket which could be converted to a nice kilt jacket, and it is not usually to hot at some times of the year to wear said jacket.

Now that being said,
Matt Newsome posted somewhere on the internet the reasons he DOES NOT wear a kilt to church, and I would suggest you consider the distraction you would cause. It is for this reason that I do not wear a kilt to church. This however is a personal choice, and the choice I made. Yours may be different.